This Hoberman sphere will surprise you with its expansion potential, but also by the fact that it glows in the dark!
Made of multiple links, this example of pure mechanical engineering genius allows this ball to grow from 9 to 30″ (23 to 76 cm)!
Includes a pulley and a booklet with 21 activities to do.
Ages 4 and up
Watch the demonstration below showing how decreasing the volume of the sphere increases the speed of rotation, demonstrating the principle of conservation of angular momentum in mechanical physics.